package com.kanavi.stand.config;

import java.util.concurrent.ThreadPoolExecutor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

/**
 * @author hailan
 * @version 1.0
 * @className ThreadPoolTaskConfig
 * @description TODO
 * @date 2020-09-02 22:00
 */
@Configuration
public class ThreadPoolTaskConfig {

  /**
   * 核心线程数（默认线程数）线程池创建时候初始化的线程数
   */
  private static final int CORE_POOL_SIZE = 10;
  /**
   * 最大线程数 线程池最大的线程数，只有在缓冲队列满了之后才会申请超过核心线程数的线程
   */
  private static final int MAX_POOL_SIZE = 100;
  /**
   * 允许线程空闲时间（单位：默认为秒）当超过了核心线程之外的线程在空闲时间到达之后会被销毁
   */
  private static final int KEEP_ALIVE_TIME = 10;
  /**
   * 缓冲队列数 用来缓冲执行任务的队列
   */
  private static final int QUEUE_CAPACITY = 200;
  /**
   * 线程池名前缀 方便我们定位处理任务所在的线程池
   */
  private static final String THREAD_NAME_PREFIX = "Async-Service-";

  /**
   * <b>taskExecutor</b> <br/>
   * <br/> bean的名称，默认为首字母小写的方法名 <br/>
   *
   * @param
   * @return {@link org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor}
   * @author thl tanghailan@88.com
   */
  @Bean("taskExecutor")
  public ThreadPoolTaskExecutor taskExecutor() {
    ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    executor.setCorePoolSize(CORE_POOL_SIZE);
    executor.setMaxPoolSize(MAX_POOL_SIZE);
    executor.setQueueCapacity(QUEUE_CAPACITY);
    executor.setKeepAliveSeconds(KEEP_ALIVE_TIME);
    executor.setThreadNamePrefix(THREAD_NAME_PREFIX);

    // 线程池对拒绝任务的处理策略 采用了CallerRunsPolicy策略，当线程池没有处理能力的时候，该策略会直接在 execute 方法的调用线程中运行被拒绝的任务；如果执行程序已关闭，则会丢弃该任务
    executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
    // 初始化
    executor.initialize();
    return executor;
  }
}